It is important for menopausal women to get bone mineral density testing, also known as bone densitometry. Bone mineral density testing is the gold standard for diagnosing osteoporosis in certain bones. From this information, your doctor can determine how strong or fragile your bones are and if you could be at risk for osteoporosis.

How Do I Prepare for a Bone Mineral Density Test?

Before having a bone mineral density test, be sure to notify your doctor if there is a possibility that you may be pregnant.

You do not have to change your daily routine before this test. Eat, drink, and take your medications as you normally would. However, do not take calciumsupplements (such as Tums) for 24 hours before the test.

What Can I Expect During the Bone Mineral Density Test?

For a bone mineral density test, you may be asked to wear a hospital gown. You will then lie on your back, on a padded table, in a comfortable position.

The lumbar spine (lower back) and the hip are the skeletal sites usually examined by bone densitometry.

The procedure can be performed by many methods:

Dual energy X-ray absorptiometry (DEXA). DEXA is the most accurate method for measuring bone mineral density. Two X-ray beams are projected onto the bones. The amounts of each X-ray beam that is blocked by bone and soft tissue are compared to estimate the bone density. DEXA scanning is fast and exposes the person to very low doses of radiation. It is used to measure bone density in the hip and spine.

Peripheral dual energy X-ray absorptiometry (P-DEXA). P-DEXA is a modification of the DEXA test. It measures bone density in outlying or peripheral areas of the body, such as the wrist. P-DEXA exposes the person to very low doses of radiation. The results can be obtained faster than DEXA. P-DEXA cannot be used to measure density of the bones in the hip and spine and it has limited usefulness for monitoring the effects of medication used to treat osteoporosis.

Quantitative Computed Tomography (QCT).This test can predict fracture risks and can monitor the effects of therapy. However, it exposes people to higher radiation doses than DEXA. QCT scanning of the spine is the most sensitive method for diagnosing osteoporosis, because it measures trabecular bone within the vertebral body. When compared to a DEXA scanning, QCT is more expensive.

Ultrasound. This method uses sound waves bounced off the bones to measure bone mineral density, usually in the heel. Ultrasound is rapid, painless, and does not use potentially harmful radiation. Ultrasound cannot be used to measure density of the bones in the hip and spine and it has limited usefulness for monitoring the effects of medication used to treat osteoporosis. This test helps predict the risks of fracture.

Dual photon absorptiometry (DPA). DPA uses a radioactive substance to produce radiation. It can measure the density of the bones of the hip and spine. DPA exposes the person to very low radiation. (Rarely used).

Your doctor will determine which approach is best for you.

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What Happens After a Bone Mineral Density Test?

After a bone mineral density test is performed, your doctor will discuss the test results with you. Generally, you can resume your usual activities immediately.